Tools



Feb. 22, 1966 s, G. YQUNG 3,235,964

TOOLS Filed May 6, 1963 FIGB.

FIG. 1. NVENrO/e United States Patent Giiee 3,235,964 Patented Feb. 22, 1966 3,235,964 TOOLS Sidney Geoirey Young, 154 Blackfriars Road,

London (SE. 1), England Filed May 6, 1963, Ser. No. 278,373 Claims priority, application Great Britain, May 10, 1962,

Claims. (Cl. 30-262) The invention relates to a tool such as a pruner or secateurs comprising two pivotally interconnected handles for moving the operative parts of the tool such as the blades or jaws that are carried thereby towiards one another into a closed position or away from one another into an open position, and a spring effective to bias the operative parts into the open or closed positions, respectively, the handles or the operative parts or any members joining or connecting the handles to the operative parts being provided with portions that are in overlapping relationship. Such a hand tool will hereinafter be referred to as of the kind indicated.

According to the invent-ion, a tool of the kind indicated can be locked in the said closed or open position to resist inuence of the said basing spring by means of a plunger which is mounted for sliding movement in one of the said overlapping portions. The plunger has an actuating member projecting from said one portion and can be pushed into engagement with an aperture provided in the other said overlapping portion, the said aperture being located so that it overlies or underlies the plunger when the tool is closed or open, respectively.

By means of the invention, a very simple catch is provided, not only 'from the manufacturing but also from the operating point of view. All that is necessary for locking is to depress the plunger when the tool is closed or open, as the case may be, accidental disengagement of the plunger from the aperture being resisted frictionally in that the plunger bears on a side of the aperture under the action of the aforementioned biasing spring which tends to open or close the tool, respectively. Preferably, the plunger is influenced to the disengaged position by a return spring so that, when slight pressure is exerted on the handles of the tool to overcome the action of the said biassing spring, the frictional resistance is overcome and the plunger moves out of engagement with the aperture.

Additional means may be provided for positively holding the plunger engaged, for example an undercut or screw thread in the wall bounding the aperture co-operating with a projection on the plunger (or a part carried by it), or a notch on the plunger co-operating with a projection on the wall bounding the aperture.

In the preferred form of the invention applied to a hand tool, the locking means are located in a position so that it can be readily actuated by the thumb or a inger of the same hand that holds the handles.

The invention will no=w be described as applied to secateu-rs but it is to be understood that it is applicable to other tools such as pliers, surgical instruments and kitchen implements.

In the examples illustrated in the accompanying drawing:

FIG. 1 is a plan view of secateurs when locked in the closed position;

FIG. 2 is an enlarged fragmentary sectional view showing the catch when the blades are open or partly open, and

FIG. 3 is a view similar to FIG. 2 but showing a modiiication of the locking means.

The secateurs comprise pivotally interconnected handles 1 having portions 2, 3 which overlap one another at least when the blades 4 are closed. A spring 5 biases the handles and blades into the open position.

The overlapping portion 2 is provided with a throughgoing stepped hole 6 accommodating a plunger or push button 7 which is provided with an actuating member 8 which normally projects from the overlapping portion 2, a collar 9 which can seat against the shoulder 11 of the stepped hole 6 and prevents complete ejection of the plunger, and a pin or stem 12 which can engage in a blind hole 13 in the overlapping handle portion 3. The pin 12 is surrounded by a coil return spring 14 for influencing the plunger 7 into a position where the pin is retracted from the overlapping portion 3.

For locking the tool in the FIG. 1 position, the handles are brought together against the action of the biassing spring 5 until the blades 4 are closed, at which time the hole 13 will be located under the pin 12. The plunger is then depressed by linger or thumb pressure exerted on the actuating member 8, thereby engaging the pin 12 in the hole 13. The force of the spring 14 is chosen to be such that, when the pin 12 is engaged in t-he hole 13, it wil-l not overcome the frictional force between the pin and the wall bounding the hole 13 as caused by the tendency of the handles 1 to move apart under the action of the spring 5 but, when such tendency is overcome by slight pressure on the handles, the plunger will be retracted automatically` The end of the pin or stem 12 may be chamfered to facilitate its entry into the hole 13 or even to act as cam means for bringing the hole 13 directly underneath it prior to locking.

In the modification of FIG. 3, the return spring 14 is of somewhat larger coil diameter and is received in a cup-shaped housing or sleeve 15 inserted in the larger diameter portion of the stepped hole 6. The internal diameter of the housing 15 is such that it acts as a guide =for the shoulder 11 of the plunger 7 which can slide therein. The base of the housing is apertured to permit passage of the pin 12 therethrough and is formed with an emplacement 16 for receiving the last turn of the return `spring 14. The advantage of this embodiment is that there can be no likelihood of the spring 14 being caught on the edge of the hole 13 in the portion 3.

Although the invention has been specifically described with reference to tools which are to be locked when closed, the converse arrangement is possible where desired.

I claim:

1. Secateurs comprising two handles, a cutting blade carried by each handle, the handles being pivotally interconnected whereby the blades can be moved towards one `another into a closed position, spring means effective to bias the blades into an open position, portions carried by the handles to be in overlapping relationship when the blades are closed, an aperture in one said overlapping portion, a plunger comprising yan actuating member and a stem mounted for sliding movement in the other said overlapping portion from a position wherein said actuating member projects from said other overlapping portion in a direction away from said one overlapping portion with said stem disengaged from said aperture to a position wherein said steam engages in said aperture when said blades are closed, means carried by said plunger and said other overlapping portion limiting the sliding movement of said plunger, a coil spring in said other overlapping portion operatively engaging the plunger whereby to bias said stem out of engagement with said aperture and a housing for said coil spring permitting passage of the stem therethrough but preventing contact between said coil spring and said one overlapping portion.

2. Secateurs according to claim 1 including cam means on said stem facilitating engagement with said aperture.

3. A hand tool having two pivotally interconnected handles, operative parts respectively carried by said handles and movable by said handles in parallel planes towards and away from one another into an end position in which said operative parts are closed and an end position in which said operative parts are open, a biasing spring effective to bias said operative parts into one of said end positions, pontions carried by said handles that lare arranged to be in `confronting overlapping relationship when said operative parts are in the other of said end positions, and means for locking said operative parts in the said other end position, said locking mean-s cornprising a push button mounted for sliding movement in one .of said overlapping portions in a direction substantially normal to said planes of movement of said operative parts, a stem on said push button, an actuating head on only one end of said stem and projecting from said one portion, a completely ciroumferentially bounded hole in the other of said overlapping portions located so that it underlies said stem when said operative parts are in said other end position, said stembeing engageable in said hole without projecting beyond said other portion, a return spr-ing etective to influence said stern out of engagement with said hole, and a cupshaped housing in said one portion accommodating said push button and said return spring, a base of said housing being apertured to permit passage of said stem therethrough but preventing contact between said return spring and said other portion. t

4. The tool of claim 3 wherein said one portion has a through going stepped passage receiving said housing, a shoulder formed by the step in said stepped passage, said push button being provided with a collar between said actu-ating head and said stern for seating against said shoulder when said stem is disengaged from sd hole.

5. The tool of claim 3 wherein said locking means are provided at a position Where they can be actuated by the thumb or a finger of the same hand that holds the handles.

References Cited by the Examiner UNITED STATES PATENTS 2,504,766 4/ 1950 Vosbikian 30-262 2,563,590 8/1951 Dolansky 30-262 2,674,796 4/ 1954 Herold 30-262 2,794,249 6/1957 Mainhardt et al. 30-262 X WILLIAM FELDMA'N, Primary Examiner.

MYRON C. KRUSE, Examiner. 

1. SECATEURS COMPRISING TWO HANDLES, A CUTTING BLADE CARRIED BY EACH HANDLE, THE HANDLES BEING PIVOTALLY INTERCONNECTED WHEREBY THE BLADES CAN BE MOVED TOWARDS ONE ANOTHER INTO A CLOSED POSITION, SPRING MEANS EFFECTIVE TO BIAS THE BLADES INTO AN OPEN POSITION, PORTIONS CARRIED BY THE HANDLES TO BE IN OVERLAPPING RELATIONSHIP WHEN THE BLADES ARE CLOSED, AN APERTURE IN ONE SAID OVERLAPPING PORTION, A PLUNGER COMPRISING AN ACTUATING MEMBER AND A STEM MOUNTED FOR SLIDING MOVEMENT IN THE OTHER SAID OVERLAPPING PORTION FROM A POSITION WHEREIN SAID ACTUATING MEMBER PROJECTS FROM SAID OTHER OVERLAPPING PORTION IN A DIRECTION AWAY FROM SAID ONE OVERLAPPING PORTION WITH SAID STEM DISENGAGED FROM SAID APERTURE TO A POSITION WHEREIN SAID STEAM ENGAGES IN SAID APERTURE WHEN SAID BLADES ARE CLOSED, MEANS CARRIED BY SAID PLUNGER AND SAID OTHER OVERLAPPING PORTION LIMITING THE SLIDING MOVEMENT OF SAID PLUNGER, A COIL SPRING IN SAID OTHER OVERLAPPING PORTION OPERATIVELY ENGAGING THE PLUNGER WHEREBY TO BIAS SAID STEM OUT OF ENGAGEMENT WITH SAID APERTURE AND A HOUSING FOR SAID COIL SPRING PERMITTING PASSAGE OF THE STEM THERETHROUGH BUT PREVENTING CONTACT BETWEEN SAID COIL SPRING AND SAID ONE OVERLAPPING PORTION. 